Update: If you are serious on getting good quality sound out from the tab, get the PowerAMP Music Player app music player (tweaking required) from android market. I have tried the app for one day and I already love it. It really changes the sound and music to a new level.
10. Viber (text and voice call) and Whatsapp for text messaging using wifi.
11. GPS essential to replace Google maps for navigation.
1. Gingerbread Keyboard works much better than default keyboard and comes in black theme, which helps save battery life (Unfortunately, Swype is better which I found it out later).
2. ezPDF for reading pdf files. It has bookmark and remembers setting that you have set for reading earlier. Works much better than Adobe reader plus it supports Colordict so you can search words while reading. Best pdf reader ever.
3. Switch Pro for better power control widget.
4. Juice Defender Plus for extend the battery life
5. PowerAmp that comes better sound quality and control for music player
6. ADWLauncher for home screen customization.
7. Beautiful Widget, well the app name explains itself.
Finally, I think Galaxy Tab 7 is great buy. It gets the job done for surfing the web, writing my work, playing some casual games, listening to music and viewing videos on the go. Although the new and more improved version of Galaxy Tab 8.9 and 10 just around the corner but I think the 7' screen is what makes it stands out.
Update: Gingerbread firmware has finally released. You can grab them from Kies software.